Manufacture of textile yarn



Aug. 31, 1943. A. s. HUNTER MANUFACTURE OF TEXTILE Y ARN Filed July 16,1940 Ricki bald 5. Hu

Patented Aug. 31, 1943 MANUFACTURE TEXTILE YARN Archibald Stuart Hunter,Kenmore, N. Y., as-

signor to E. L du Pont de Nemours a Company Wilmington, DeL, acorporationof Delaware Application July 16, 1940, Serial No. 345,778

2 Claims.

This invention relates to the manufacture of textile yarn. Morespecifically, itrelates to a process of producing novelty yarn composedof two or more strands of filaments, said strands having shrunkunequally during the production thereof to form a pebbly yarn structure.

Novelty yarns which are a composite of two or more single yarns ofdifferent lengths are known to the art. Such multiple yarns are producedby combining two or more single yarns having different shrinkagecharacteristics and thereafter subjecting the yarn to a shrinkingtreatment. In U. 8. Patent No. 1,976,201, a method is described forproducing multiple yarn from cellulose acetate, wherein two yarns comingfrom a spinning machine are subjected to diiferent degrees ofstretching',then are combined'into one strand and finally thrown on a'down-twister and collected on a bobbin. Thedegree of tension on one ofthe yarns is such that the yarn is stretched beyond its elastic limits.The composite yarn on the bobbin is subjected to thecustomaryafter-treatment procedure and then to, a. shrinking treatment. Thefilaments or the yarn which was subjected to the higher tension, willshrink to a greater degree and will, therefore, be

shorter than those of the yarn which was subjected to the lower tension.

Novelty or composite yarns made from cellu- Other objects of thisinvention will appear hereinafter.

The objects of this invention are accomplished, in general, by spinningseveral regenerated cellulose yams, or similar acid coagulated yarns,under diflerent tensions but without exceeding the elastic limit of theyam, .combining the yarns while still in the gel stateand twisting thesev- 'eral yarns, for example, into a bucket in accordance with thebucket spinning process.

' ner, the yarn is still in a strained condition, it

still retains the capacity to shrink. It possesses,

therefore, residual shrinkage which may be i measured or determined bysubjecting the yarn to a boil-oi! procedure which comprises, forexample, treatment of the yarn with a hot bath and permitting the sameto dry without restraint.

For convenience, the present invention will be described with particularreference to the pro cellulose compositions such as ethyl cellulose.

yond the elastic limit thereof exhibits the higher degree of shrinkageand becomes the core, or the shorter member, of the composite yarn.

It'is an object of this'invention to provide a process for producing arippled novelty yarn wherein the ripples are quite pronounced.

Another. object of this invention is to provide a process for theproduction of a rippled, or pebbly, novelty yarn during the conventionalsteps of spinning and purification, without the necessity of havingadditional shrinking and drying pro- It is a further object of thisinvention to provide a yarn which when woven into fabric will give depthto the fabric, thereby eliminating the uninteresting fiat appearancecommon to most fabrics.

The invention is also applicable to the productio of yarn by thecuprammonium process.

Referring to the accompanying drawing wherein Fig. 1 is a diagrammaticillustration of one arrangement for carrying out the tension spinningand doubling ste s of this invention, and

Fig. 2 is a diagrammatic illustration of--an arrangement for carryingout the tension-free dr ing step, this invention may, for example, becarried out as follows: Two yarns A and B freshly spun from spinneret Iand 2 respectively, into a spinning or coagulating bath 3 are; whilestill and fed into bucket 6, preferably at equal rates of speed, duringwhich procedure the two yarns are twisted together and collected as acake 1. While the combined yarn is still in the gel state, it is woundon reel 8 from cake 1 to form skeins. The skeins are allowed to dryfreely while under notension. The ripple develops as one componentshrinks on drying more than the other. Any other suitable expedient forspinning one yarn at a. higher tension than the other may of course beemployed.

Surprisingly, the yarn which was spun at the lower tension shrank to aconsiderably greater degree than the other yarn. This component was,therefore, shorter in the shrunken yarn and consequently constitutes thecore, while the other yarn spun under the higher tension forms/ theripples and gives the novelty efiect.

The following examples illustrate several detailed processes forcarrying out the present invention.

Example I Viscose was spun through two identical spinnerets mounted sideby side in a coagulating and regenerating bath to form yarns which werecontinuously removed, combined into one strand, and collected on abobbin at a take-up speed of 2,000 inches per minute. The spinneretscontained 40 holes each. The diameter of the holes was 0.0035 inch. Theyarn from one of the spinnerets, yarn A, was a 3'70-clenier, IO-filamentyarn and was spun with a 6-inch bath travel. The

other yarn, yarn B, was a 3'70-denier, LO-filament yarn and was spunwith a 90-inch bath travel.

' The combined yarn collected on the bobbin was washed acid-free on thebobbin and while still in the wet gel state, thrown on a downtwisterwhich applied 3 turns per inch to the yarn. The

gel yarn was immediately reeled to skein and while in a completelyrelaxed state, was allowed to dry. During the drying, yarn component Awhich was spun under low tension decreased in length 9.8%, while yarncomponent B which was spun under a higher tension decreased in length4%. The differential shrinkag obtained was therefore 5.8%. Because ofthe shrinkage difference, yarn component A became shorter than theother, said component becoming the base'yarn, while yarn component B wasloosely twisted thereabout.

Example II washing, desulfuring and bleachin in that form. r

The two yarns were combined by twisting together on a downtwister whilestill in the wet gel state. The combined yarn was then reeled to skeinsand dried in the relaxed state. Yarn A which was spun under low tensionpossessed a gel shrinkage on drying of 6.2%, while yarn B had a shrinkagof 2%, giving a differential shrinkage of 4.2%. A yarn effect similar tothat of Example I was obtained.

Example III Yarn B of Example II while in the gel state was combined ona downtwister with yarn made as follows: A high salt index viscose, saidindex being 8, modified with 5% sodium sulfate was spun into acoagulating regenerating bath to give a yarn of 370-denier, -fi1ament,using a 6-inch 'bath travel and collected on a bobbin. The

combined yarns after purification were reeled to skeins and allowed todry. Th gel shrinkage of the yarn spun from the high index viscose was12.1%, while that of yarn B was 2%, giving a differential shrinkage of10.1%. A yarn having a pronounced ripple eflect was obtained, the effectbeing produced by the long and short components thereof.

Example IV Two yarns having different filament sizes and spun underdifferent tensions were produced as follows. Yarn A which was a370-denier, 10-filament yarn was spun through a spinneret having 10holes, each hole being 0.012 inch in diameter, using a 6-inch bathtravel and collected on a bobbin. Yarn B which was a IO-denier,40-filament yarn was spun through a spinneret having 40 holes, each holebeing 0.0035 inch in diameter, using a SO-inchbath travel and collectedon a bobbin. The two yarns were washed and purified on the bobbin andthrown on a downtwister which applied 3 turns per inch to the yarn. The

wet yarn was immediately reeled to skeins and or more times the spinningtension of the other component yarn or yarns. The high differentialshrinkage of the component yarns is believed due to the fact that theyare combined to form a composite yarn while still in the wet gel state.The yarn according to this invention is distinguished from that of theprior art in that the base yarn or the short yarn is the one which wasspun under the lower tension. The present invention is furtherdistinguished by the fact that the gel shrinkage between yarns spununder different tensions diifers to a greater degree than the residualshrinkage of the same yarn. By.,this fac,t,.it has been possible'toobtain novelty yarns having a more pronounced ripple effect than wasproduced by the prior art. For the production of a satisfactory noveltyyarn in accordance with the present invention, it is essential that theshrinkage difference between the yarns must be in excess of 3%. For thebest results, the shrinkage difierential between the two yarns should befrom 5% to 10%, or even higher.

Th gel shrinkage of a yarn increases with an increase in filamentdenier, an increase in the total denier, and with a decrease of spinningtension. If two gel yarns are combined which have a wide difference infilament denier, a wide difference in total denier, and which were spununder widely different tensions, a high gel shrinkage differential willbe obtained. Two yarns. which are identical with the exception that onehas been spun under a much higher tension than the other, will give asatisiactory shrinkage differential though not as high as when allcontrolling factors have been utilized.

In the above examples, several ways or producing the novelty yarn ofthis invention have been described. The invention is not to be limitedto these examples since it is possible to v y the conditions of spinningthe yarn and still obtaimyarns having different gel shrinkage values.For example, a diiferent denier yarn may be obtained by maintaining allconditions the same, with the exception of the'pump delivery which maybe increased for one of the yarns. The denier may be further increasedby slowing down the take-up of the yarn. The denier difierential may befurther effected by using spinnerets having large orifices.

In the examples, processes have been described in which the'yarns whenreeled to skeins were acid-free and in some cases purified. It is to beunderstood that satisfactory results, and in some cases moresatisfactory results may be obtained by a process in which acid gelyarns'are reeled to skeins and dried in the relaxed state.

' The spinning tension to which the yarn is sublected may be controlledby the length of bath travel. It may be further effected by the use of aseries of rollers in the bath around which the yarn must travel.Additional tension may be applied by providing said rollers with vanes.

This invention has been described in terms of a yarn containing twocomponents, but it' is obvious that three, or in some cases four or morecomponents yarns may be twisted together to produce the composite yarn.

The present invention is described with particularreference to theproduction of regenerated cellulose from viscose solutions. Theinvention is, however, generally applicable to the production of yarnfrom any aqueous cellulosic solution which is coagulable' in an acidcoagulating bath. Production of cellulosic yarns from aqueous solutionswith the coagulation of the aqueous solutions in an acid or neutral bathwill be referred to herein as a "wet spinning process.

In the process described in the examples, the

yarn was reeled to skeins and allowed to dry while relaxed. The processis not to be limited,

however,todryingtheyarninskeinformassatisfactoryresultswillbeobtainedbyanyprocessinwhichtheyarnisdriedwhilerelaxed,

The process of this invention makes it possible to produce a noveltyrippled yarn during the standard steps of spinning and purification. It

is not necessary, therefore, to provide more than less slippery hand.The kinky, rippled yarn of this invention possesses the furtheradvantage over the prior art yarns in that the 'ripples are permanentand will not be pulled out on stretch- Since it is obvious that manychanges and modifications can be made in the detailed processes abovedescribed without departing from the nature and spirit of the invention,it is to be understood that the invention is not to be limited except asset forth in the appended claims.

I claim:

1. In the method of making a rippled composite yarn by wet spinning, atdifferent spinning tensions, aplurality of yarns or different denierscomposed of artificial cellulosic filaments, the improvements comprisingapplying to-the yarn of least denier a spinning tension at least twotimes the spinning tension of the yarn of largest denier, doubling saidyarns, and drying the doubled yarns while they are still in the gelstate bysupporting them in a loose condition free from tension.

2. In a method of making a rippled composite yarn by wet spinning, atdifierent spinning tensions, a plurality of yarns of diil'erent filamentdeniers composed of artificial cellulosic filamerits, the improvementscomprising applying to the yarn of'least filament denier, a spinningtension at least two times the spinning tension of the yarn of largestfilament denier, doubling said yarns, and drying the doubled yarns whilethey ares'tillinthegelstatebysupportingthemina loose condition free fromtension.

' ARCHIBALD STUART HUNTER.

